Fix issue 19424

pkg/analyzer/lib/src/generated/resolver.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library engine.resolver;
 
 import 'dart:collection';
 import "dart:math" as math;
 
 import 'java_core.dart';
@@ skipping 7905 matching lines @@
   }
 
   @override
   void define(Element element) {
     if (!Scope.isPrivateName(element.displayName)) {
       super.define(element);
     }
   }
 
   @override
+  Source getSource(AstNode node) {
+    Source source = super.getSource(node);
+    if (source == null) {
+      source = _definingLibrary.definingCompilationUnit.source;
+    }
+    return source;
+  }
+
+  @override
   Element internalLookup(Identifier identifier, String name, LibraryElement referencingLibrary) {
     Element foundElement = localLookup(name, referencingLibrary);
     if (foundElement != null) {
       return foundElement;
     }
     for (int i = 0; i < _importedNamespaces.length; i++) {
       Namespace nameSpace = _importedNamespaces[i];
       Element element = nameSpace.get(name);
       if (element != null) {
         if (foundElement == null) {
@@ skipping 7557 matching lines @@
   /**
    * Return the tag that has the given identifier, or {@code null} if there is no such tag (the
    * identifier is not defined).
    *
    * @return the tag that has the given identifier
    */
   String getTagWithId(String identifier) {
     return idToTagMap[identifier];
   }
 }